[tz] New Yorker article on David Mills and NTP

[Paul Eggert]

On 10/6/22 13:40, Brooks Harris via tz wrote:
>> Predicting length of day (LOD) is a tricky business with no real 
>> consensus.
> ...  From what I can tell C04 is *the*
> 'consensus' of LOD as a matter of practical common use.

Sure, but C04 describes LOD in the past. I was referring to LOD in the 
future. C04 is published with 30-day latency which is not enough for 
some apps, and I think even the IERS Daily Rapid EOP data have one-day 
latency. So even if you want to know LOD "now" you need to predict based 
on what it was earlier; and of course if you want to know LOD next week 
you must predict. Michalczak and Ligas[1] have a brief summary of some 
competing prediction approaches in their introduction.

If you want to predict LOD for the next five millennia, which is what I 
had been talking about, the error bars get considerably larger and it is 
indeed a tricky business.

[1] Michalczak M, Ligas M. The (ultra) short term prediction of 
length-of-day using kriging. Adv Space Res. 2022;70(3):610-620. 
https://doi.org/10.1016/j.asr.2022.05.007